As a growing number of Viagra lawsuits continue to be filed by men nationwide, each involving allegations that Pfizer failed to adequately warn about the risk of melanoma linked to the blockbuster erectile dysfunction drug, the U.S. District Judge presiding over all federal cases has issued an order outlining the discovery process concerning general causation in the litigation.

There currently about 200 cases pending against Pfizer nationwide, which are consolidated in the federal court system as part of an MDL, or Multidistrict Litigation. To prevent duplicative discovery into common issues, avoid conflicting pretrial rulings and serve the convenience of the parties, witnesses and the courts, the litigation is centralized before U.S. District Judge Richard Seeborg in the Northern District of California for pretrial proceedings.

In a pretrial order (PDF) issued September 26, Judge Seeborg laid out the schedule and requirements during the discovery process into the link between Viagra and melanoma, as well as other issues that are not specific to any one plaintiff. This includes the exchange of written discovery, Pfizer’s production of documents, depositions of Pfizer fact witnesses and discovery concerning general causation experts.

According to the schedule, discovery will commence with the production of documents immediately. By October 31, plaintiffs will identify custodians for whom Pfizer shall product documents, and production must be completed by February 20, 2017. Depositions of Pfizer fact witnesses are to be completed by August 30, 2017, with designation of general causation experts and reports late next year, and all depositions of these experts completed by March 30, 2018.

In addition to discovery into the link between Viagra and melanoma, it is expected that Judge Seeborg will establish a bellwether process, in which case-specific discovery will be completed on a small group of cases in the MDL. These cases would be prepared for a series of early trial dates, which are designed to help the parties gauge how juries may respond to certain evidence and testimony that is likely to be repeated throughout the litigation, potentially facilitating eventual Viagra settlement agreements between the parties.

The order issued this week established deadlines for filing of challenges to the admissibility of expert testimony and other general causation issues during the first half of 2018, which means that the first cases are unlikely to be ready to go to trial for at least two years.

Viagra Melanoma Side Effects

Viagra (sildenafil citrate) was introduced by Pfizer in 1998, and it has become one of the most widely recognized brand-name medications on the market in the United States, used by millions of men to treat impotence and sexual dysfunction, including the inability to develop or maintain an erection.

Since its approval, Viagra has been prescribed to an estimated 35 million men, and is generally considered safe by most consumers. However, recent studies suggest that the medication may reduce the body’s ability to resist the spread of melanoma.

Plaintiffs allege that Pfizer knew or should have known about the Viagra cancer risk for years, indicating that studies published as early as 2011 suggested that the erectile dysfunction drug may promote melanoma cell invasion. Another study published in the Journal of Cell Biochemistry in 2012 also found that PDE5 inhibitors like Viagra could exacerbate melanoma development.

The American Cancer Society indicates that melanoma is diagnosed in about 69,000 Americans each year and causes about 8,650 deaths annually. The skin cancer usually manifests as unusual moles or patches of skin. While it is often curable if caught early, once melanoma has spread beyond the skin and local lymph nodes, treatment is difficult and it may ultimately result in death.